A headline scrolls on a television screen on the floor of the New York Stock Exchange, Wednesday, Oct. 10, 2018. Stocks are extending their slump on Wall Street, led by drops in big technology companies, as rising bond yields draw investors out of stocks. (AP Photo/Richard Drew)

U.S. stocks plunged to their worst loss in eight months on Wednesday as technology companies continued to drop. The Dow Jones Industrial Average fell 831 points.

The losses were widespread, and stocks that have been the biggest winners on the market the last few years, including technology companies and retailers, suffered steep declines. Apple and Amazon both had their worst day in two and a half years.

The Nasdaq composite, which has a high concentration of technology companies, had its biggest loss in more than two years. Alec Young, managing director of global markets research at FTSE Russell, said investors fear that rising interest rates and growing expenses are going to erode company profits next year.

“The tax cuts juiced earnings this year and that’s not sustainable,” he said. “The market’s starting to say that the glass may be half empty.”

The S&P 500 index sank 94.66 points, or 3.3 percent, to 2,785.68. The benchmark index fell for the fifth straight day, which hadn’t happened since just before the 2016 presidential election.

The Nasdaq composite tumbled 315.97 points, or 4.1 percent, to 7,422.05. It’s fallen 7.5 percent in just five days.

The Dow Jones Industrial Average gave up 831.83 points, or 3.1 percent, to 25,598.74. The Russell 2000 index of smaller-company stocks shed 46.45 points, or 2.9 percent, to 1,575.41.

After a long stretch of relative calm, the stock market has suffered sharp losses over the last week as bond yields surged. Stocks had come close to big drops in the last few days, but each time they recovered some of their losses. That didn’t happen Wednesday as stocks fell further late in the day.

Apple gave up 4.6 percent to $216.36 and Microsoft dropped 5.4 percent to $106.16. Amazon skidded 6.2 percent to $1,755.25. Industrial and internet companies also fell hard. Boeing lost 4.7 percent to $367.57 and Alphabet, Google’s parent company, gave up 4.6 percent to $1,092.16.

Insurance companies dropped as Hurricane Michael continued to gather strength and came ashore in Florida bringing winds of up to 155 miles an hour. Berkshire Hathaway dipped 4.7 percent to $213.10 and reinsurer Everest Re slid 5.1 percent to $217.73.

The biggest driver for the market over the last week has been interest rates, which began spurting higher following several encouraging reports on the economy. Higher rates can slow economic growth, erode corporate profits and make investors less willing to pay high prices for stocks.

The 10-year Treasury yield remained at 3.20 percent, about where it was late Tuesday, after earlier touching 3.24 percent. It was at just 3.05 percent early last week and 2.82 percent in late August.

Technology and internet-based companies are known for their high profit margins, and many have reported explosive growth in recent years, with corresponding gains in their stock prices.

Gina Martin Adams, chief equity strategist for Bloomberg Intelligence, said the stocks have become more volatile in the last few months because investors have concerns about their future profitability.

“Amazon recently announced they were increasing wages, Facebook is spending a ton on security,” she said. “Semiconductors have the most exposure to China out of segments in the S&P 500.”

Sears Holdings nosedived after the Wall Street Journal reported that the struggling retailer hired an advisory firm to prepare a bankruptcy filing that could come within days. The stock fell 16.8 percent to 49 cents. It was more than $40 five years ago.

Sears has closed hundreds of stores and sold several famous brands or put them on the block as it sees more customers abandon its stores.

Benchmark U.S. crude oil fell 2.4 percent to $73.17 a barrel in New York. Brent crude, the international standard, lost 2.2 percent to $83.09 a barrel in London.

The CAC 40 in France dropped 2.1 percent, Germany’s DAX lost 2.2 percent and the FTSE 100 in London fell 1.3 percent.

Stocks from emerging markets were also hard hit. Investors see many of these countries as being vulnerable to higher U.S. interest rates, which can pull away investment dollars. Brazil’s Bovespa lost 2.5 percent and the Merval in Argentina sank 2.2 percent.

The dollar fell to 112.59 Japanese yen from 113.05 yen late Tuesday. The euro rose to $1.1525 from $1.1496. The British pound rose to $1.3197 from $1.3146.